Piezoelectric/electrostrictive element, method of manufacturing piezoelectric/electrostrictive element, piezoelectric/electrostrictive device, and method of manufacturing piezoelectric/electrostrictive device

1. A piezoelectric/electrostrictive device comprising laminated piezoelectric/electrostrictive elements disposed on a ceramic substrate, said piezoelectric/electrostrictive elements having a structure in which a piezoelectric/electrostrictive layer and internal electrode layers are stacked in an interdigitating comb-shaped pattern, an uppermost, exposed surface of at least one of said piezoelectric/electrostrictive elements being defined at least in part by an outermost electrode layer,

wherein said internal and outermost electrode layers have respective ends projecting outwardly from a side face of said piezoelectric/electrostrictive layer on a side surface at which the laminated state of said piezoelectric/electrostrictive layer and said internal electrode layers is exposed, and

wherein a distance by which said ends project outwardly from said side face is equal to or smaller than one half of the thickness of said piezoelectric/electrostrictive layer between said internal electrode layers.

2. A piezoelectric/electrostrictive element according to claim 1 , wherein said distance is in a range from 0.5 μm to 2 μm.

3. A piezoelectric/electrostrictive element according to claim 1 , wherein said internal and external electrode layers include a cermet.

4. A piezoelectric/electrostrictive device according to claim 1 , wherein said device is obtained by a cutting process after a sintering process.

5. A piezoelectric/electrostrictive device according to claim 4 , wherein said respective ends projecting outwardly from said side face are obtained by a heat treatment after said cutting process.

6. A piezoelectric/electrostrictive device according to claim 5 , wherein said piezoelectric/electrostrictive elements are heat treated at a heat treatment temperature for a period of time where said temperature and said period of time are indicated by an area surrounded by a critical curve beyond which a metal contained in said internal and external electrode layers is deformed and a critical curve beyond which said metal contained in said internal and external electrode layers is ruptured or a critical curve beyond which said piezoelectric/electrostrictive layer is decomposed.

7. A piezoelectric/electrostrictive device according to claim 5 , wherein said heat treatment is performed at a temperature from 600 to 1000° C.